The invention relates to a feed mixing apparatus for use wherever livestock is cared for and fed. A farmer or rancher has an obligation every day of the year to mix and deliver feed for animal consumption. There are also many other daily chores to which to attend. The "feed time" chore must be handled in the shortest possible time at the lowest possible cost, using inexpensive and easily maintained equipment and wasting little of the feed constituents or the mixed feed.
The scope and content of the prior art has been determined. (See, form PTO-1449 in the file wrapper.) The most relevant prior art is: AG, U.S. Pat. No. 3,415,492, 12/1968, Rule; AF, U.S. Pat. No. 3,358,973, 12/1967, Mitchell et al; AA, U.S. Pat. No. 761,541, 5/1904, Ransome; and AC, U.S. Pat. No. 1,861,146, 5/1932, Jaeger.
Rule dealt generally with apparatus for mixing and dispensing feed for animal consumption. He explained the desirability of feeding animals a complete mixed ration of cracked grain, which would include ground cracked grain, protein supplement, minerals, vitamins, feed additives and roughage.
In Rule, the mixing unit 30 includes a cylindrical drum 31 used as the central component of a system of conveyors for receiving feed constituents from storage and dispensing mixed feed for consumption. The mixing unit 30 has an input section 29 and an output section 32 at opposite ends of the rotatable drum 31 which has internal rigidly positioned spiral (continuous or interrupted) blade flights 41. The input section 29 is connected to the drum interior by a cylindrical "boot" or pipe 33. An auger drive shaft 37 extends from the input section 29 through the pipe 33 into and through the drum 31 axially of the spiral blades 41. Within the input section 29, the auger flighting 38 has an effective diameter equivalent to the internal diameter of the pipe 33. Within the drum 31, the auger flighting 40 has a greater efective diameter; a radial depth such that there is approximately a two-inch clearance, represented at 42, between the outer edge of the auger flighting and the edges of the spiral blades 41.
The Rule concept is that the rotating auger flighting 40 will move the feed constituents lengthwise in the mixing drum 31 in the direction from the intake end toward the output section 32. The operation of the oppositely rotating spiral blades 41 is not to convey the feed constituents lengthwise within the drum; but rather, to "pick up the grain or heavier more seperable particles and lift them to the top of the drum whereupon they again drop onto the materials carried by auger flighting 40, which are continuously involved or more so with the lighter and more bulky materials such as chopped ensilage or hay." Rule, col. 4, 11. 47-52.
To the person of ordinary skill in the art of feed mixing, it is apparent that the compromise between a shearing and moving action for the auger 40 and spiral blade 41 components of Rule, the optimum 2-inch clearance, requires an extremely high power input using large amounts of energy. Also, the length of the drum is relatively long. Further, unmixed feed components from the output section 32 falls onto the wagon 10 and are put through the mixing drum again--"As a general rule, the load of unmixed feed components is put through 11/3 times." Col. 6, 11. 18 and 19.
Mitchell et al discloses a portable mixing apparatus, for accurately mixing two or more dry materials with one or more liquids. The apparatus has a frame 10 with rollers 13 to rotatably support the mixing drum 14. As in Rule, the mixing action is "pass-through."
Ransome discloses (FIG. 3) a rotatable cylindrical drum with dual internal spiral mixing and conveying blades mounted on a frame.
Jaeger discloses a rotatable mixing drum with an auger shaft positioned axially of spiral blades.
The above discussed prior art all deal generally with the problems encountered in "mixing" and present solutions therefor. It has now been found that feed mixing apparatus may be portable, efficient, inexpensive to acquire and to operate, and easy to maintain.